From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
For testing, for instance, running one thread per cpu in a CPU socket,
testing isolation of groups of cores that share memory cache.
[root@emilia ~]# ~acme/bin/cyclictest -nmu -p95 -a 1,3,5,7
policy: fifo: loadavg: 0.00 0.17 2.48 2/409 25640
T: 0 (25636) P:95 I:1000 C: 15503 Min: 4 Act: 4 Avg: 4 Max: 8
T: 1 (25637) P:95 I:1500 C: 10331 Min: 4 Act: 4 Avg: 4 Max: 7
T: 2 (25638) P:95 I:2000 C: 7745 Min: 4 Act: 4 Avg: 4 Max: 8
T: 3 (25639) P:95 I:2500 C: 6193 Min: 3 Act: 4 Avg: 4 Max: 8
[root@emilia ~]# tuna -t cyclictest -CP
thread ctxt_switches
pid SCHED_ rtpri affinity voluntary nonvoluntary cmd
25635 FIFO 2 0,2,4,6 449 16 cyclictest
25636 FIFO 95 1 4471 1 cyclictest
25637 FIFO 95 3 2977 1 cyclictest
25638 FIFO 95 5 2230 1 cyclictest
25639 FIFO 95 7 1782 1 cyclictest
[root@emilia ~]#
And generally to allow starting multiple threads spread over non
contiguous CPUs.
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
src/cyclictest/cyclictest.8 | 3 ++-
src/cyclictest/cyclictest.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+), 1 deletions(-)
diff --git a/src/cyclictest/cyclictest.8 b/src/cyclictest/cyclictest.8
index fbb6174..fc76e31 100644
--- a/src/cyclictest/cyclictest.8
+++ b/src/cyclictest/cyclictest.8
@@ -34,7 +34,8 @@ A summary of options is included below.
.\" For a complete description, see the Info files.
.TP
.B \-a, \-\-affinity[=PROC]
-Run all threads on procesor number PROC. If PROC is not specified, run thread #N on processor #N.
+Run all threads on procesor number PROC. If PROC is not specified, run thread #N on processor #N. If a CSV PROC list is specified, start a thread on each,
+for starting multiple threads on non-contiguous (enumeration) CPUs.
.TP
.B \-b, \-\-breaktrace=USEC
Send break trace command when latency > USEC. This is a debugging option to control the latency tracer in the realtime preemption patch.
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 11b6cea..26ba18f 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -980,11 +980,13 @@ static int quiet;
static int interval = DEFAULT_INTERVAL;
static int distance = -1;
static int affinity = 0;
+static int *affinities;
static int smp = 0;
enum {
AFFINITY_UNSPECIFIED,
AFFINITY_SPECIFIED,
+ AFFINITY_SPECIFIED_LIST,
AFFINITY_USEALL
};
static int setaffinity = AFFINITY_UNSPECIFIED;
@@ -1034,6 +1036,33 @@ static char *policyname(int policy)
return policystr;
}
+static int read_affinities(char *list, int max_cpus)
+{
+ char *token = list;
+
+ affinities = malloc(sizeof(int) * max_cpus);
+
+ if (affinities == NULL)
+ return -1;
+
+ num_threads = 0;
+
+ do {
+ affinities[num_threads] = atoi(token);
+ if (affinities[num_threads] >= max_cpus)
+ return -1;
+ token = strchr(token, ',');
+ if (++num_threads > max_cpus)
+ goto out_free;
+ } while (token++ != NULL);
+
+ return 0;
+out_free:
+ free(affinities);
+ affinities = NULL;
+ return -1;
+}
+
/* Process commandline options */
static void process_options (int argc, char *argv[])
@@ -1097,6 +1126,10 @@ static void process_options (int argc, char *argv[])
if (optarg != NULL) {
affinity = atoi(optarg);
setaffinity = AFFINITY_SPECIFIED;
+ } else if (optind<argc && strstr(argv[optind], ",")) {
+ if (read_affinities(argv[optind], max_cpus))
+ fatal("invalid affinity list\n");
+ setaffinity = AFFINITY_SPECIFIED_LIST;
} else if (optind<argc && atoi(argv[optind])) {
affinity = atoi(argv[optind]);
setaffinity = AFFINITY_SPECIFIED;
@@ -1588,6 +1621,7 @@ int main(int argc, char **argv)
switch (setaffinity) {
case AFFINITY_UNSPECIFIED: par->cpu = -1; break;
case AFFINITY_SPECIFIED: par->cpu = affinity; break;
+ case AFFINITY_SPECIFIED_LIST: par->cpu = affinities[i]; break;
case AFFINITY_USEALL: par->cpu = i % max_cpus; break;
}
stat->min = 1000000;
--
1.7.1
--
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